/**************************************************************************************
* Copyright (C) 2008 EsperTech, Inc. All rights reserved. *
* http://esper.codehaus.org *
* http://www.espertech.com *
* ---------------------------------------------------------------------------------- *
* The software in this package is published under the terms of the GPL license *
* a copy of which has been included with this distribution in the license.txt file. *
**************************************************************************************/
package com.espertech.esper.epl.join.exec.base;
import com.espertech.esper.client.EventBean;
import com.espertech.esper.epl.expression.ExprEvaluator;
import com.espertech.esper.epl.expression.ExprEvaluatorContext;
import com.espertech.esper.epl.join.rep.Cursor;
import com.espertech.esper.epl.join.table.PropertyIndexedEventTable;
import java.util.Set;
/**
* Lookup on an index using a set of expression results as key values.
*/
public class IndexedTableLookupStrategyExpr implements JoinExecTableLookupStrategy
{
private final PropertyIndexedEventTable index;
private final int streamNum;
private final EventBean[] eventsPerStream;
private final ExprEvaluator[] evaluators;
/**
* Ctor.
* @param index - index to look up in
*/
public IndexedTableLookupStrategyExpr(ExprEvaluator[] evaluators, int streamNum, PropertyIndexedEventTable index)
{
if (index == null) {
throw new IllegalArgumentException("Unexpected null index received");
}
this.index = index;
this.streamNum = streamNum;
this.eventsPerStream = new EventBean[streamNum + 1];
this.evaluators = evaluators;
}
/**
* Returns index to look up in.
* @return index to use
*/
public PropertyIndexedEventTable getIndex()
{
return index;
}
public Set<EventBean> lookup(EventBean theEvent, Cursor cursor, ExprEvaluatorContext exprEvaluatorContext)
{
Object[] keys = new Object[evaluators.length];
eventsPerStream[streamNum] = theEvent;
for (int i = 0; i < evaluators.length; i++) {
keys[i] = evaluators[i].evaluate(eventsPerStream, true, exprEvaluatorContext);
}
return index.lookup(keys);
}
public String toString()
{
return "IndexedTableLookupStrategyExpr expressions" +
" index=(" + index + ')';
}
}